I'm getting interested in the above named chips. As the PIC16F1459, it has the same pinout as the PIC16F690 which I already use, but it has all kinds of improved features, including USB, and the chip can adjust its internal oscillator to match the incoming USB signal, so it can be accurate enough for USB without needing a crystal. Then it is fast, up to 48MHz, and has two memory pointers and a much larger RAM space. And it costs less than $2.

I'm wondering if anyone has used these chips, and what the support from any particular compiler was like. Have the compiler manufacturers responded to the additions? And is the PIC16F1459, even if it's loaded with good features, basically a dead end because everyone has moved to the PIC18F's or better?

That chip is kind of 18F chip with a 16F badge. I would say any chip that can do job for you more or less seamless is a good chip. So it is more a question about what you feel comfortable with. Since Microchip introduced the XC8 compiler that support both 16F and 18F series. It is not a problem using both series.

As far as I'm concerned, USB is a case of "Do not meddle in the affairs of wizards". I've used the FTDI interface chip (designed by the best wizards in Scotland, no doubt) and it was brilliant--looks like a serial line to both the computer and the microcontroller. If I manage to get the USB port running on this PIC processor, it'll be someone else's code and not mine, for sure.

Another neat feature of the PIC16F1459 which I forgot to mention is that it has automatic context saving during interrupts. It saves the most important registers when the interrupt is entered and then restores them when you do a return instruction. That is a very nice saving of time to service an interrupt.